<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .container {
            position: relative;
            width: 400px;
            height: 400px;
            border:1px solid #ccc;
        }
        .item {
            width: 100px;
            height: 100px;
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            margin: auto;
            text-align: center;
            line-height: 100px;
            border:1px solid #ff0000;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="item">111</div>
</div>
</body>
</html>
